'''
@Company: TWL
@Author: xue jian
@Email: xuejian@kanzhun.com
@Date: 2020-06-30 09:50:07
'''
'''
剑指 Offer 09. 用两个栈实现队列
用两个栈实现一个队列。队列的声明如下，请实现它的两个函数 appendTail 和 deleteHead ，分别完成在队列尾部插入整数和在队列头部删除整数的功能。(若队列中没有元素，deleteHead 操作返回 -1 )

 

示例 1：

输入：
["CQueue","appendTail","deleteHead","deleteHead"]
[[],[3],[],[]]
输出：[null,null,3,-1]
示例 2：

输入：
["CQueue","deleteHead","appendTail","appendTail","deleteHead","deleteHead"]
[[],[],[5],[2],[],[]]
输出：[null,-1,null,null,5,2]
'''


class Solution:
    def __init__(self):
        self.stack1 = []
        self.stack2 = []

    def appendTail(self, value: int) -> None:
        self.stack1.append(value)

    def deleteHead(self) -> int:
        if self.stack2:
            return self.stack2.pop()
        elif self.stack1:
            while self.stack1:
                self.stack2.append(self.stack1.pop())
            return self.stack2.pop()
        else:
            return -1



# Your CQueue object will be instantiated and called as such:
# obj = CQueue()
# obj.appendTail(value)
# param_2 = obj.deleteHead()


if __name__ == "__main__":
    solution = Solution()
    method = ["appendTail","deleteHead","deleteHead"]
    value = [[3],[],[]]
    re = []
    for i in range(len(method)):
        if value[i]:
            re.append(eval('solution.'+method[i])(value[i][0]))
        else:
            re.append(eval('solution.'+method[i])())
    print(re)
